Idiopathic atrophoderma of Pasini and Pierini(IAPP)is an uncommon condition of unknown eti-ology and typically affects persons in the second and third decades of life.IAPP consists of asymptomatic grey to brown depressed lesions with "cliff drop "borders,which are usually bilateral and located on the trunk. A 40-year-old woman visited our department because of unilateral atrophic lesions on the abdomen, right arm,and posterior aspect of right thigh for 20 years.Laboratory evaluations were normal and histologic examination revealed significantly decreased thickness in dermis. We report an unusual case of idiopathic atrophoderma of Pasini and Pierini presenting unilateral distribution.(Ann Dermatol 14(1)35-37,2002).